Venetian blinds employ horizontal slats, supported on cords. By rotating a shaft in the head of the blind, the cords can be altered in length thus rotating the slats to close or open the blind.
The drive system for driving such a horizontal shaft usually consists of some form of gear drive usually a worm and gear, and a rod or so called "wand" hanging downwardly from the gear drive. The wand can then simply be grasped in the hand and rotated, thereby opening and closing the blind.
For reasons of aesthetics and economy, the mechanism used in such blinds and the cords and the like are relatively small and delicate, and must be handled with a certain degree of care. If for example the wand is rotated too far some damage may be caused.
Such over vigorous rotation may be caused by a careless person, or not infrequently by children playing with the blinds.
In order to overcome this problem, it has been proposed to incorporate a form of clutch mechanism in the gear drive itself.
This is a relatively complex solution to the problem and somewhat increases the cost of the gear drive. The market for blinds is highly competitive and many blind manufacturers do not choose to use the more expensive form of drive. In addition, different blind manufacturers employ various different assemblies and lay outs, and it is not always possible to incorporate a gear system having a clutch in their own particular design.
A further problem relating to the drive system for slat rotators, is the connector between the wand and the drive system.
Generally speaking some form of simple universal coupling connector is provided at the top end of the wand, where it is connected to the gear drive system. This permits the wand to hang down perpendicular, and yet enables a person to swing the wand out, if they should want to, for operation.
Some manufacturers employ a wire loop and sleeve. Others employ a moulded hook at the top of the wand. The use of the wire loop and sleeve involves a minor additional expense, and also requires a certain amount of skill and time during assembly.
The incorporation of a moulded connector on the wand itself is considered a more desirable solution. In the past however, the hooks which have been used have also been a source of problems, since they are liable to break again due to careless handling.